On the Modeling of Some Anti-inflammatory and Anti-thrombotic Drugs by AM1

Two families of autacoids from cell membrane phospholipids have been identified. The first, the icosanoids, which are formed from arachidonic acid, include prostaglandins and leukotrienes. The other includes modified phospholipids, as the platelet aggregating factor (PAF). These compounds are related to inflammatory and cardiovascular diseases. We review in this paper some of the work that has been done in our laboratories in the last few years relating to the modeling of new potential thromboxane synthase (TXS) and 5-lipoxygenase (5-LO) and cyclooxygenase (COX) inhibitors, and TXA₂ receptor antagonists derived from nitrogenated heterocycles. We include the results of the modeling of a group of proposed PAF antagonists, and compare their structures with PAF itself and with a recently proposed PAF antagonist model. This revised version was published online in June 2006 with corrections to the Cover Date.     

An improved method to detect β- galactosidase activity in transgenic mice: a post-staining procedure on paraffin embedded tissue sections

The Escherichia coli -galactosidase gene is frequently used as a reporter gene in transgenic studies because its activity can be easily detected at the cellular level. Here we report a procedure for monitoring -galactosidase activity directly in tissue sections, which involves the use of a mixture of ethanol and poly-ethylene-glycol as a fixative (Kryofix) and a special paraffin characterized by a lower fusion point of 42 °C. After embedding and cutting, the sections are stained by the chromogenic substrate 5-bromo-4-chloro-3-indoyl--d galactopyranoside (X-Gal). This procedure allows both the retention of a high level of -galactosidase activity and the preservation of good tissue morphology. Furthermore, it can be combined with immunohistochemical methods to detect other cellular components without compromising reporter gene detection     

Seasonal variation of nitrification along a salinity gradient in an urban estuary

A review on salinity adaptation of marine molluscsbased on mainly Russian scientific literature ispresented. The existence of two relativelyindependent systems of adaptation to extreme(resistance level) and moderate (tolerance level)changes of environmental salinity was shown. Theresistance of molluscs is based mainly on an impededwater-salt exchange with the external medium due tomantle cavity hermetization. The tolerance ofmolluscs is determined by cellular mechanisms ofadaptation. Reversible changes of protein and RNAsynthesis, alteration of the pattern of multiplemolecular forms of different enzymes, and theregulation of ionic content and cell volume wereshown to be of importance for the above mentionedmechanisms. The efficiency of resistance andtolerance adaptations to salinity changes may varyin different species and in different colourphenotypes of the same species (intrapopulationalpolymorphism). Parasites (trematodes) may suppressthe resistance of the mollusc-host to extremesalinity changes without effecting the host'scapacity for adaptive changes in salinitytolerance.     

Time linkages between pollination onsets of different taxa over an 11-year period in Perugia,Central Italy

Times of pollination of different taxa in the atmosphere of Perugia (Central Italy) over an 11-year period (1982–1992) were recorded and analysed by means of a 7-day volumetric Hirst-type pollen trap. For some taxa, the pollination period varied from year to year from a chronological and/or quantitative point of view. Several taxa showed a linkage in their starting dates of pollination. Knowledge of this kind of linkage allows us to build a forecasting model.     

Ecomorphological correlates in ten species of subtropical seagrass fishes: diet and microhabitat utilization

Synopsis Ecomorphological correlates were sought among ten species of distantly related subtropical seagrass fishes. Morphometric data associated with feeding and microhabitat utilization were compared by principal components analysis, cluster analysis, and canonical correspondence analysis to dietary data. Morphology was generally a poor predictor of diet except for a group of mid-water planktotrophic filter feeders. Separation of the species along morphological axes appears to be related more to microhabitat utilization resulting in three major groups: (1) a group of planktotrophic, mid-water fishes specialized for cruising and seeking out evasive prey characterized by a compressed fusiform body, forked caudal fin, long, closely spaced gill rakers, short to intermediate! length pectoral fin, pointed pectoral fin, large lateral eye, short head, and a terminal or subterminal mouth; (2) slow swimming, less maneuverable epibenthic fishes that pick or suck their prey off the substrate. They are united by more rounded caudal and pectoral fins, and short or no gill rakers; and (3) a group of more mobile and maneuverable epibenthic foragers characterized by a more compressed, sub-gibbose body, long, pointed pectoral fins, forked caudal fins, large lateral eyes, subterminal mouth, and greater jaw protrusibility. Cases of convergence in trophic and microhabitat utilization characters were apparent in some of the groups.     

Changes in the surface morphology of the rabbit endometrium related to the estrous and progestational stages of the reproductive cycle

Summary Changes occurring on the surface of the uterine luminal epithelium of the rabbit during the estrous and progestational stages of the reproductive cycle were examined by scanning and transmission electron microscopy. The findings demonstrate that the uterine epithelium, or endometrium, contains two cell types: ciliated cells and nonciliated, microvillous cells. In estrous animals, ciliated cells, although not very numerous, were usually observed in small groups. However, at increasing intervals of time following mating, ciliated cells progressively disappeared from the endometrium until approximately eight to ten days post coitum, when they became scare. From several hours to four to five days following mating, extensive changes occurred on the surfaces of microvillous cells. When observed by TEM, these elements contained organelles typical of cells involved in the synthesis and secretion of glycoproteins. Furthermore, microvillous cells during this period displayed numerous apical protrusions of different sizes and shapes and containing material of varying electron density. Parallel SEM examinations of the same material confirmed the presence of these protrusions. Some of the protrusions appeared as spheroidal masses attached to the cytoplasm by means of a cytoplasmic strand. Other surface masses were clearly unattached to the cell surface and were distributed (1) on the surface of microvillous cells, (2) on the cilia of adjacent ciliated cells, and (3) on the surface of spermatozoa.Changes occurring on the luminal surface during the early postcoital period are interpreted as an expression of morphodynamic processes likely involving coupled secretion (exocytosis) and resorption (endocytosis) of luminal material. The observations presented here also demonstrate that between six and ten days post coitum, the rabbit endometrium contained increasing numbers of enlarged, nonciliated cells that probably arose by the fusion of smaller, microvillous elements.The work reported here was supported by C.N.R. contracts No. CT 760128809 and CT 77014239 (to P.M.) and NIH. Grant HD-04274 (to J.V.B.)     

Hemoglobin adducts and urinary mercapturic acids in rats as biological indicators of butadiene exposure

Binding of 1,2-epoxy-3-butene, the primary metabolite of butadiene, to hemoglobin (Hb) and excretion of its mercapturic acid in urine were studies as potential indicators of butadiene exposure. Four groups of Wistar rats were exposed to butadiene at 0, 250, 500 and 1000 ppm 6 h/day, 5 days/week, during 2 weeks. Blood was collected at the end of exposure and 17 days later for analysis of hemoglobin adducts and adduct stability. Urine was collected each day during exposure (afternoon samples) and in between exposures (morning samples). Adducts of 1,2-epoxy-3-butene to N-terminal valine in Hb were measured using the N-alkyl Edman procedure and GC/MS of the thiohydantoin derivatives. The corresponding mercapturic acid was analysed, after deacetylation, through derivatization with phthaldialdehyde and HPLC with fluorescence detection. The Hb adducts proved to be stable and are therefore useful for dosimetry of long-term exposure to butadiene. The adduct levels increased linearly with exposure dose up to 1000 ppm (3 nmol/g Hb at 1000 ppm). The increase with exposure dose of the mercapturic acid concentration in urine was also compatible with a linear does response up to 1000 ppm. The sensitivity of both analytical methods needs to be improved for their application to human samples.     

Seasonal fluctuations of zooplankton biomass in Lake Xolotlán (Managua)

Seasonal fluctuations of zooplankton biomass (dry weight) were determined during a year in two localities of Lake Xolotlán (Managua). Biomass estimations of the most common species of rotifers, cladocerans and copepods were made. The maximal zooplankton biomass was observed in February–April (dry season) in coincidence with the period of highest phytoplankton abundance. Copepods contributed with 78% and 84% to the mean zooplankton biomass at points 1 and 7, respectively. Cladocera biomass was lowest during most of the year, and it was probably controlled by fish predation. Development of rotifer biomass was more intense during the rainy season, when detritus particles were more abundant. Daily fluctuations of zooplankton biomass were not pronounced.